Potato starch – also known as potato flour – is extracted from potatoes. The cells of the root tubers of the potato plant contain starch granules (leucoplasts). To extract the starch, the potatoes are crushed and the starch grains are released from the cells. The starch is then washed out and dried to powder. Potato starch has been produced in the same basic way for centuries – actually even the ancient Incas knew how to make potato starch.
Potato starch contains typical large oval spherical granules; their size ranges between 5 and 100 μm. Potatoes’ starch granules are roughly twice as big as other starch granules (tapioca or grain starches) resulting in much higher water absorption capacity and better texture. Potato starch is a very refined starch, containing minimal protein or fat. This gives the flour a clear white colour, and the cooked starch typical characteristics of neutral taste, good clarity and transparency, high binding strength, long texture and a minimal tendency to foaming or yellowing of the solution.
Potato starch contains approximately 800 ppm phosphate bound to the starch; this increases the viscosity and gives the solution a slightly anionic character, a low gelatinisation temperature (approximately 60 °C) and high swelling power. These typical properties are used in food and technical applications.
Untreated starch requires heat to thicken or gelatinize. When a starch is pre-cooked, it can then be used to thicken instantly in cold water. Cold-swelling or pre-gelatinized (pre-gel) potato starch is starch cooked and then dried on a drum dryer or in an extruder making the starch cold water soluble. This is a physical modification of the starch. The starch remains a native starch and can be declared as such. Aloja Starkelsen SIA produces drum-dried pre-gelatinized or cold-swelling potato starch. Chemically modified starches are not allowed in organic food processing
As an additive for food processing, food starches are typically used as thickeners and stabilizers in foods such as puddings, custards, soups, sauces, gravies, pie fillings, and salad dressings, and to make noodles and pastas. Potato starch may be used in all traditional recipes replacing any other starch – and in most cases giving better functionality. Organic potato starch adapts extremely well to organic processing.
- Water binder
- Anti caking ingredient
- Bulking ingredient
- Glueing agent
The most popular application areas are in:
- Meat industry
- Dry blends
Potato starch and potato starch derivatives are used in many recipes, for example in noodles, wine gums, cocktail nuts, potato chips, hot dog sausages, bakery cream and instant soups and sauces, in gluten-free recipes, in kosher foods for Passover and in Asian cuisine. In pastry, e.g. sponge cake, it is used to keep the cake moist and give a soft texture. It is also occasionally used in the preparation of pre-packed grated cheese, to reduce sweating and binding. Helmipuuro, traditionally consumed in Finland, is a porridge made from monodisperse grains of potato starch and enjoyed with milk. The Helmi potato granules are produced by Finnamyl Ltd.
- Fresh dairy spreads…
- Fresh dairy desserts and ice cream…
- Fruit preparations…
- Cured meats and poultry…
- Bread and pastry…
The Swelling Process
While heating potato starch in a water dispersion the granules start to take up water and swell. When the temperature has reached approximately 60C the granules are so swollen that they start to create viscosity. Further heating increases the viscosity and the granules become like balloons. At approximately 75C the granules are swollen to their maximum. Further heating starts to break the granules which continues until all the granules are completely broken into a solution. When cooling the solution retrogradation takes place and a gel is created. The exact process depends on the concentration of the starch and other solids that are present.
All these different phases offer different functionality and possibilities for food processing in temperatures that are applicable in most food processing. Therefore organic potato starch is a functional ingredient in numerous potential application areas. Understanding this process and what possibilities it gives is even more important in organic food processing where chemical starch modifications are not allowed.
See also the blog posting Starches as alternative to some additives
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